1. Field of the Invention
The present invention relates to a water jet propulsion boat.
2. Description of the Related Art
A water jet propulsion boat generates propulsion power in a boat body using a jet of water from a water jet propulsion mechanism. The water jet propulsion boat is provided with a reverse gate which changes the orientation of the jet of water. It is possible for the reverse gate to be moved to, for example, a forward position or a reverse position. The reverse gate changes the orientation of the jet of water to the front of the boat body in the reverse position. Due to this, the boat body reverses. Alternatively, the speed of the boat body in the forward direction is reduced.
It is necessary for the movement of the reverse gate to be performed after the propulsion power of the water jet propulsion mechanism has been sufficiently reduced. For example, a vessel which is disclosed in U.S. Pat. No. 7,708,609 is controlled so that, when the rotation speed of the engine is larger than a predetermined rotation speed when a lever is being operated, the rotation speed of the engine is reduced so that the rotation speed of the engine is equal to or less than the predetermined rotation speed, and after that, the reverse gate is moved. Alternatively, in a personal water craft (PWC) which is disclosed in U.S. Pat. No. 5,755,601, the position of the reverse gate is set based on an operation signal from both a throttle lever and a brake lever. In the PWC, the reverse gate is set at either a forward position, a reverse position, or a neutral position according to a combination of the presence or absence of the operation of the throttle lever and the brake lever.
In the vessel which is disclosed in U.S. Pat. No. 7,708,609, the rotation speed of the engine is reduced without relation to the lever operation amount. As a result, it is not possible to obtain a natural speed reduction performance according to the lever operation amount. In the same manner, in the PWC disclosed in U.S. Pat. No. 5,755,601, it is not possible to obtain a natural speed reduction performance according to the brake lever operation amount.